The Innovative Solution to Turbo Lag: Audi's Electric Supercharger
In this video, we're exploring how Audi is eliminating turbo lag through the use of the world's first production electric supercharger. This innovative solution uses an electric motor to drive a compressor wheel, providing instant boost and eliminating the delay associated with traditional turbochargers.
The Air Flow: Breaking Down the Complexity
Initially, air flows into one of the turbochargers, passing through an air filter before splitting into two separate paths. The air then travels through two intercoolers, where the valve controlling access to the second turbocharger is blocked off. This allows the air to pass through only one intercooler before being split between the two intake manifolds for each cylinder bank.
As the engine operates at higher RPMs, the low-to-mid range exhaust valves are closed, and the compressor wheel pulls in air directly into the eight cylinders. However, as the engine reaches mid-range RPMs, the valve opens again, allowing both turbochargers to come online. The system is designed to split the exhaust gases between the two turbochargers, acting like a single turbo engine during low-to-mid range and a twin-turbo engine in higher RPM ranges.
The Limitations of Electric Turbochargers
One common misconception about electric turbochargers is that they can be easily added to any car. However, this is not the case due to power limitations. Using a 12-volt battery system would not be enough to provide sufficient power for the compressor wheel, and aftermarket solutions claiming otherwise are often exaggerated.
Audi's Solution: A 48-Volt System
To overcome these limitations, Audi developed a separate 48-volt system specifically designed for the electric supercharger. This system is capable of delivering 7kW or 9.5hp, significantly more power than a standard 12-volt battery system. By adding this additional power source, Audi was able to develop an efficient and effective solution to turbo lag.
The Added Complexity and Cost
While the electric supercharger provides numerous benefits, it also comes with added complexity and cost. The system requires the addition of a generator, a 47-watt-hour 48-volt battery, an electric supercharger, a DC-DC converter, and associated piping and electrical connections. This increased complexity makes it less feasible for mass production and more suitable for high-end vehicles like the Audi SQ7.
The Benefits of Electric Supercharging
Despite the added cost and complexity, electric supercharging offers several benefits, including improved performance, reduced turbo lag, and enhanced fuel efficiency. In the case of the Audi SQ7, this innovative solution enables the vehicle to accelerate quickly and efficiently, making it a compelling option for those seeking high-performance capabilities.
In conclusion, Audi's electric supercharger represents a significant step forward in the development of efficient and effective turbocharging solutions. By harnessing the power of electricity, they have eliminated turbo lag and improved performance, making their vehicles stand out from the competition.
"WEBVTTKind: captionsLanguage: enHello everyone and welcome!in this video, We are talking about how Audi iseliminating turbo lag through the use of the world's first production electric supercharger.So, traditionally, superchargers are run off of the engine. In this case, the engine is powering a three-kilowatt generator,which is powering a 48-volt battery,which is then powering a seven-kilowatt electric motor, which is powering the compressor sideThat compressor to pull an additional air to compensate for turbo lag.So Audi is calling this an electric-powered compressor, you can think of it as an electric supercharger.Where instead of the engine driving it, you have an electric motor driving that compressor wheelSo first I want to talk about the air flow.Looking at the engine it can look a bit complicated as what's going on, so I've broken it down here on the whiteboardso we can kind of figure that out.So, initially, you're just pulling in the air through one of those turbochargers.So you've got your air filter, the air comes through that first turbo charger, a valve for the second turbocharger is off.Blocked off so you can't have air coming through there. That air then travels split between two different intercoolers,and then at this intercooler this valve will be open right here. Let's saywe're not using the electric supercharger, then the air passes through comes, combines, and then it's split between the two intake manifoldsfor each of the cylinder banksThen it goes from all eight of these cylinders to this single exhaust right here before passing out the back.Now, we'll get into the different stages as it gets that into higher rpm,but essentially how this electric supercharger works is, when you initially press on the gas you want thatinstant response. You don't want turbo lag and so that's where the electric motor comes in.In less than a quarter of a second it can spool up to70,000 rpm and provide that immediate boost to fill the delay of turbo lag before, you know, the mainturbocharger has started spooling up. So you'll have this valve closed off right here,and then the compressor wheel will pull air directly, push that into the eight cylinders.Now that's when you initially press on the gas.As you start to get into you know those those low to mid higher RPMs,the low to mid rpm range,then you start to just rely on the turbocharger itself once those exhaust gasses have been built upand you no longer need this electric supercharger to compensate for the lag.So then you're just running on this single turbocharger.And then as you start to get to that mid-range rpm, into the higher rpm, and you're still asking for full power,they've actually split now where they'll power both turbochargers and in this caseYou'll have air coming through both of them. This valve right here will be open so you're now pulling in air through both turbochargers,you're powering both turbochargers,and you'll have sufficient boost for that mid to high rpm range whileOperating under full throttle. So, they've also done a super clever thing here with the exhaust valves, and so, the wayIt's split up is on the low rpm side,you're only using a single exhaust valve for each cylinder and all of that air is being routed to the firstturbocharger. And then there's a variable valve systemWhich will activate the second exhaust valve, and that second exhaust valve for each cylinder goes to the second turbocharger.So, each cylinder has one exhaust valve that powers each turbochargerand you'll just use the one exhaust valve for those low to mid rpm ranges,and then you'll use both exhaust valves to power both turbos for that higher rpmregion where you want more power and you want to be able to take advantage of using both turbos.So it will act like a single turbo engine low to mid, and then mid to high rpm it will act like a twin turbo engineas it splits that exhaust gasesinto both of them.Now a lot of people wonder why you can't just slap on an electric turbo on any car.You've got a 12-volt battery system,why can't you just use that to you know bring in more air?And really it comes down to power so those,there are aftermarket ones that'll say, like, it's an electric supercharger and it's powered off your 12-volt battery.Those are nonsense, they don't have enough power to actually do anything.And so that's what I kind of want to discuss here. So, the reason Audi put in a 48 volt systemis to be able to power this seven-kilowatt motor.You need a significant amount of power to pull in a lot of air, and to do that very quickly.So power is equal to current X voltage. So if you have 145-amps, you multiply that by 48-volts,which is what this battery delivers, and that gives you 7kW or 7,000W about 9.5hp.If you're using a 12V system, you've got 145-amps X 12V, you're only producing 1.75kWand, you know, this is a huge demand. Your car battery already has plenty of things it's powering. All the on-board electronics,you know your HVAC system,plenty of different things, your sound system,so it's got its responsibilities on the car, the spark for the engine, in the case of gasoline engines.It has its responsibilities and considering, you know, the idea of putting on an electric supercharger on top of that, just simply isn't feasible.There's not enough power to do it. So that's why Audi added this separate 48 volt system,and this means adding a lot of stuff to the engine. This is why it's not done on every car out there.It's because it's expensive, and it could, you know, it's of course complicated to do so you're addingYou know you're adding a generator to the system. You're adding a470-watt hour,48 volt battery to the system, you're adding that electric supercharger to the system,and all the associated piping that goes along with it, and you're also adding a DC to DC converter,48-volt down to 12-volt for other on-board systems, and this is all in addition to the 12-volt battery system that's already on the car.So, you know, this isn't something that can be cheaply done. Hence, It's in, you know, a super nice, expensive, Audi SQ7.Really nice, quick, SUV. And so, you know, in a more expensive car it makes sense, in cheaper carsIt's not a simple solution, as of the added complexity and cost that goes along with it.But I think one of the really important things to understand is that it takes a lot of power to do this.It's not something that you can, you know, depend on a 12 volt battery to do for your car.So, if you guys have any questions or comments, of course feel free to leave them below.Thanks for watching!\n"
